What’s it about? A compendium of stories featuring Marco Polo, “Sticky-Mitt Stimson” and “Scooby the Five Star Reporter”. Oh, and this thing called “Superman”… Creators Jerry Siegel and Joe Shuster edited down their unsold newspaper strip at short notice, to produce a tale about Superman’s origin and first adventures. There’s no mention of Krypton, but baby Supes is dispatched to Earth by his father from “a distant planet” suffering a cataclysm. He grows up in an orphanage, learns he has super-strength and super-speed, and can leap great heights and long distances (no flying yet). As an adult he adopts the name Clark Kent, solves a murder, humiliates a wife-batterer and rescues Lois Lane from gangsters – and all in 13 pages!

Why so valuable? There are probably no more than 100 copies left in the world, and not many are in anything approaching decent condition. A copy found recently insulating a wall in a house in Minnesota “only” fetched $175k. The copy that once belonged to Nicolas Cage, on the other hand, was the first comic ever to break the $2m barrier at auction.